Build one travel set, not a scatter of papers
Gather the documents this trip actually needs into a single set before you pack anything else: the vaccination record, the microchip number written out in full, a health certificate if your route or carrier requires one, proof of ownership, and your contact details with a second number for someone at home. Travellers lose dog paperwork one sheet at a time, usually because the rabies page lived in a coat pocket while the microchip card stayed in a glove box. One set, in one place, removes that slow scatter.
Carry the originals on you, copies elsewhere
Put the originals in a waterproof pouch that travels in your own hand luggage or day bag, never in a checked bag or in the boot under other luggage. Place a full set of clear copies in a different bag, so a single lost bag cannot take both. Add a digital copy you can open without a signal, because hotel desks, ferry staff and boarding facilities will often accept sight of a clear copy while you arrange a replacement for a missing original.
Check validity windows before you leave home
Some travel documents only count inside a set window, and a health certificate issued too early can be worthless by the day you travel. Read each document against your travel dates while you can still fix a problem: confirm names and microchip numbers match letter for letter across every page, check that vaccinations will still be in date on the return leg, not just the outward one, and confirm the certificate covers the exact route. A mismatch between the microchip number on paper and the chip in your dog is the kind of small error that becomes a long delay at a desk. Keep a photograph of the microchip card on a second family member's phone as well, so the number survives even if your own phone is the thing that gets lost on the journey.
Plan for the loss you hope never happens
Note the phone numbers for your vet, the microchip database and your accommodation in the same pouch, so a lost set comes with its own recovery plan. If papers do go missing mid-trip, contact your vet first: practices can usually reissue vaccination records and confirm chip details to a facility that is holding your dog. Tell the microchip database promptly if the chip card is lost with identifying details on it, and keep your own contact information current there, since that database is what a finder will rely on.
Refile everything the day you get home
Travel has a way of returning documents to the wrong envelopes, so empty the pouch on the day you return and put each sheet back into your dog's main file while you still remember which copy is which. Replace any copy that came home creased or water-marked, and note any document a carrier queried so you can strengthen it before the next trip. Travelling with that checked, backed-up set inside your dog's Pet Passport on KinsLe gives you a portable records packet that survives a lost pouch, a dead phone battery and a last-minute change of route.